The present invention relates to a deep-drawable film which (based on 100 parts by weight of plastic in the film) comprises from about 1 to 60% by weight of at least one partially crosslinked EPDM, from about 12 to 30% by weight of a propylene homopolymer, copolymer or graft polymer with or without reactive groups, from about 77 to 9.5% by weight of at least one polymer and/or ionomer containing reactive groups which is based on ethylene and methacrylic acid or acrylic acid, some of the acid groups containing a metal ion or being neutralized by metal ions, and from about 10 to 0.5% by weight of at least one polymeric crosslinking agent which contains reactive groups and comprises more than 51% by weight, (based on 100 parts by weight of the crosslinking agent) of ethylene or other olefin groups and 1 to 49% by weight of acrylate and/or methacrylate groups and reactive groups, the reactive groups being epoxy, isocyanate, ketone, aldehyde, silane, alkyl halide and/or anhydride groups, and, if desired or required, at least one filler, additive and/or processing aid.
According to the invention, the film is a deep-drawable laminated film which contains a polyolefin-containing top film and at least one polyolefin-containing bottom film, which differs qualitatively and/or quantitatively from the composition of the top film and has the above-enumerated polymer components, and, if required, a surface protection layer. The top film has a certain composition in accordance with the present invention.
A very wide range of films based on polyolefins, and in particular those based on polypropylene with polyethylene, and the processing thereof are already known (cf. inter alia FR-A 2017705). However, depending on the field of use, the requirements which the films have to meet are so varied and are associated with increasing demands, so that there is a need for films having improved processing possibilities.
U.S. Pat. No. 5,206,294 discloses a polymer blend which contains partially crosslinked EPDM, polypropylene, polymers or ionomers containing reactive groups and a polymeric crosslinking agent containing reactive groups. The monofilms produced therefrom are readily deep-drawable but do not have other properties required by the automotive industry.
In connection with this invention, a large number of tests were carried out with film formulations, in which, inter alia, those which contained a crosslinked PP-EPDM and an uncrosslinked propylene block copolymer or heterophase propylene block polymer were tested. These films have good grain stability and have a certain degree of dulling or a certain dullness, as desirable in many fields of use (for example, interior lining in automobiles or the like).
However, the film having this composition has the disadvantage that it is poorly deep-drawable, since the grain stability is partly lost. The result is therefore that the deep-drawability of the film is in need of improvement.
The hitherto known processes for dulling flexible PP-EP or PP-EPDM compositions with mineral fillers, for example, talc, result in an increase in the rigidity and a deterioration in the aging behavior. Furthermore, the matte effect is greatly influenced by the degree of deformation. The use of elastomeric particles in rubber blends (cf. inter alia EP-B 0257242) is also unsuitable.
Plastic films have to meet special requirements for the production of deep-drawable automotive films or webs or automotive film layers, since different deep-drawing conditions must be maintained in the same molding. Nevertheless, the molding should have the same embossed structure and dullness in all parts. On the other hand, special requirements are set with regard to the scratch resistance of the plastic surfaces, fog values, the aging stability and the like.